Subdural Empyema

The subdural space is a potential space defined by the endothelial lining of the inner surface of the dura and the arachnoid. In most series, subdural empyema is a disease of older children, adolescents, and young adults and occurs secondary to infection in the paranasal sinuses (frontal and ethmoid) in two thirds of patients or the middle ear and/or mastoid infection in one fifth of patients. Hematogenous spread to a preexisting subdural collection and rupture of a parenchymal brain abscess into the subdural space account for the remainder of spontaneously occurring subdural empyemas.Prior to the development of the sinuses in childhood, infections in the subdural space may be due to spread from contiguous scalp or calvarial infection, meningitis, hematogenous spread to a preexisting subdural hematoma, or may follow subdural punctures or subdural or ventricular shunt placement. Subdural empyemas have been reported complicating penetrating wounds, following the application of skull tongs or pins, and craniotomy.